Missed outpatient clinic appointments are common among HIV-infected patients engaged in clinical care. Compounding the negative health consequences for individual patients, missed appointments have important implications for HIV transmission, including spread of resistant virus, a serious public health consideration. Adherence to outpatient HIV clinic appointments has been notably understudied. The goals of this proposal are to provide insight on barriers to HIV appointment adherence in an underserved population, to generate knowledge regarding the impact of missed appointments on clinical outcomes, and to develop a clinical tool to identify patients at high risk for future missed visits. Collectively, this research will provide a framework that will inform a theory-based intervention to improve HIV appointment adherence, as well as a foundation for a sustainable research program dedicated to studying HIV health services utilization and adherence to care. The research plan is driven by a unified conceptual model, linked with explicit measurement instruments, and a detailed analysis plan. The specific aims for this proposal are to: Specific aim 1: Determine barriers and facilitators to outpatient HIV clinic appointment adherence among African American patients lacking private health insurance; Specific aim 2: Derive and internally validate a novel, point-of-care prediction rule to identify patients at high risk for outpatient HIV clinic appointment non- adherence and; Specific aim 3: Evaluate potential dose-response relationships between non-adherence to outpatient HIV clinic appointments and important clinical outcomes. Specific aim 1 will be accomplished through qualitative methods, specifically Nominal Group Technique. The 2nd and 3rd specific aims will be accomplished through a prospective cohort study at the DAB 1917 HIV/AIDS Clinic. This research will expand upon the Principal Investigator's past training and research by taking advantage of an outstanding mentoring and research environment, allowing him to acquire new skills in the conduct of patient-oriented HIV research, so that he will become an independent investigator improving the health of people with HIV. Lay statement: Among persons with HIV, missed clinic visits are common and may contribute to the spread of HIV to others. This research seeks to better understand reasons that HIV patients miss clinic visits.